High-potential switch.



PATENTED MAY 9, 1905.

Atty.

lam LeR-Emmet Edward M. Hewett,

mix

lm/entorst Wll W. LI R. EMMET n E. M. HEWLETT.

HIGH POTENTIAL SWITCH.

APPLIGATION FILED 1313.14, 1901. RENBWBD JAN, 11. 1905.

Witnesses UNITED STATES Patented May 9, 1905.

PATENT OFFICE.,

1V ILLIAM L. R. vEMMET AND EDlVARl) M. HEVLET", OF SOHENEOTADY,

NEWT YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A OOR- PORATION OF NEV YORK.

HIGH-'POTENTIAL SWITCH.

SPECIFICATION forming part of Letters Patent No. 789,597, dated May 9, 1905.

Application filed February 14, 1901. Renewed January 11, 1905. Serial No. 240,574`

T0 al?, whom, t Wray concern.-

Beit known that we, VILLIAM LF. R. EM.- MET and EDWARD M. HEWLETT, citizens of the United States, and residents of Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in High-Potential Switches, o'f which the following is a specification.

This invention relates to high-potential switches or circuit-breakers of the oil-break type, in which the circuit is ruptured at contact-points under an insulating fluid. 1n the construction of switches of this type oil is commonlyT employed as the medium in which the circuit is opened and is well adapted 'for the purpose, both on account of its high insulating properties and by reason of its liquid character, by reason of which it closes in around the points of contact across the are and serves to condense and mechanically displace the arc-vapors and Vfill the space with a medium of high insulating power. The employment of oil, however, is accompanied by some disadvantages, one of which is the carbonization of the oil and the deposit of soot on the terminals and adjacent parts. When. the circuit is opened, the small arc formed reduces some of the oil, setting 'free the basic carbon in the form o'f fine particles, which 'float in the oil and gradually agglomerate and form deposits on the terminals and adjacent parts, which unless removed interfere with the operation of the switch.

1t is the object of one part of our invention to avoid this di'fliculty, to which end we proceed 'by mounting the movable element of the switch or circuit-breaker so that in opening the circuit it takes a downward movement in the oil, thereby effecting the contact on the under surface of the fixed terminal, which will be rendered self-cleaning by the engagement of the parts and from which the carbon will fall and settle in the bottom of the containing vessel. Another advantage incidental to this organization is that by reason of the downward movement of the movable contact the are lengthens or is stretched through a progressively-increasing depth of liquid, thereby subjecting the are stream to an increasing pressure and also giving the insulating vapors developed a longer path to travel in the cool liquid before reaching the air. This results in. a decreased fire hazard, since it sometimes happens that the vapors liberated by the heat of the arc escape in sufficient volume to reach the top of the containing vessel and may be ignited there. A further improved action Afollows from the fact that the contact is made in the upper part of the oil-bath, which is cleaner than the lower parts, as thc carbon and other foreign matter settles toward the bottom. le eilect also an improved action of the oil at thepoints of contact b y constructing the movable terminal so as to create as little disturbance of the oil as possible. Eddy-currents in the body of the oil are apt to render irregular the flow of liquid across the arc stream in the act of extinguishment. le Yfind that by shaping the movable element so that it presents a symmetrical tapering edge in the direction of its movement in the oil it cleaves the latter more readily and by preventing eddies, or at least rendering them uniform, permits the oil to close in around the surface of rupture uniformly. Our invention comprises also improved means 'for operating the switch, by means of which a compact organization is provided and safety of operation assured. Ve provide a system of bell-crank levers for raising and lowering the contacts and a toggle which may be cramped when the contacts are set in engagement, placing them in tight fixed relation to one another.

The several features of novelty will be more particularly pointed out hereinafter and will be definitely indicated in the appended claims.

1n the accompanying drawings, which illustrate our invention, Figure 1 is a scctional view e'f a switch or circuit-breaker embodying our improvements, and Fig. 2 is a sectional view on a plane at right angles to that shown in Fig. 1..

The type of switch shown in the drawings ed for triphase alternating currents.

is one adapted 'for mounting on a switchboard. lt comprises an oil-tank 1, formed of galvanized sheet-iron and having overlapping oints riveted and soldered to make them {luid-tight, across which are run a series of wooden partitions 2 2, dividing the tank into a plurality oit independent compartments for the several contacts. The tank is lined with wood or other insulating material, as indicated. The partitions 2 2L not only 'form independent oil-chambers for the contacts, but act as barriers to prevent an arc 'from striking across from one contact to another. The iixed terminals of the circuit are mounted in a cast-metal cover 3, which is provided with an extension 3, forming a support for the controlling-levers and to permit its attachment to the rear of the switchboard 4. The fixed terminals are mounted in porcelain bushings 5 6 7 5, &c., which may be `firmly seated in the cover by a lead joint, as indicted at S. The bushing is recessed at both ends, the upper end 'forming a socket for a lead irom the high-potential circuit, which is led through it without removing its insulating compound or braiding, as seen in Fig. 2. 'To the bared end of one of these cables is secured a copper or phosphorbronze rod 9, the under side of which is threaded and adapted to receive the contact-clip 10, 11, or 12. After the latter are screwed Vlirmly home the free space around the cable is 'filled with an insulating compound containing asphaltum or other material which will adhere to the walls of the porcelain and which will form a good joint with the compound with which the braiding of the cond uctor is saturate l. Thus all metallic parts are deeply embedded beneath the surface of a rigid insulating compound, which prevents the entrance of moisture, and the tendency oi current to jump through the air if the latter is moist is greatly reduced, since before doing so it must break down the solid dielectric, which is impervious to moisture. The insulating-bushings are made sulficiently long to dip well into the oil-bath in the several compartments, the oil-level being indicated in the drawings. No claim is herein made to the specific means for insulating the terminals, as it is covered in an application in the name of Charles C. Badeau. rlhe vlixed contact-clips 1() 1.1 12 are arranged in pairs, one pair o1 which may be placed in cach compartment. These clips are Yformed of a solid block of brass or phosphor-bronze, which 'forms the terminal and upon which are riveted lour or more yielding spring-contacts of phosphor-bronze, as indicated in the drawings, to which may be attached arcing shoes or tips 13.

The switch shown in the drawings is adapt- This, however, is shown merely by way of example, since our improvements are applicable to high-potential currents ol any kind whatever. The switch. shown, therefore, is ol the triple-pole double-break type, two breakingpoints in each limb of the triphase circuit being provided. As will be evident from Fig. 2, the contacts are arranged in pairs, each pair et contacts being bridged or adapted to be bridged by a brass conductor1-1. This conductor is mounted on the end ol the wooden rod 1.5, the several rods being screwed into a common casting, to which is attached a bell-crank lever 16. rl`he lframe carrying the wooden rods is connected to the bell-crank lever 16 by a loose oint, and slots are provided, as indicated at 17, to permit the rods to yield laterally in their bearings when the bell-crank lever is raised. or lo\\'crcd. The lever 16 is pivoted on a part ot the cover at a point 1S about midway between the upper and lower limits ol movement ot the swinging end. lonnected to the other crank ol the lever 16 is a link 1Q, to which is pivoted a l'iell-crank lever 20, controlled by an operating-handle 21 on the vl'ront ot the board. through the link 24. The link 1S) and the cooperating arm ol the lmll-crank level' 2() arc so arranged that they lorm a toggle, as indicated in Fig. 1, which when the operatinglever 21 is forced home (the position indicated in Fig. 1) is cramped oll center, thereby locking the parts in a position where the switch is closed. A stop 22 limits the movement of the operating-lever. The length olt the levers in the operating system is so regulated th at they do not strikeone another in the several ranges ot movement. The movable bridging contacts 14, &c., are provided at the top with a lirusto-pyramid al contact adapted. to slide into engagement with the shoes ol'v the 'lixed contact-cli ps on the lour sides, as indicated in Figs. 1 and 2, and the lower sides of the bridges are tapered or otherwise shaped so as to gently and symmetrically displace the liquid when the switch is lowered in opening the circuit. te have shown this bridgingcontact as having a pointed nose which shears the liquid somewhat atter the l'ashion of the bow of a boat and prevents any violent disturbance on the liquid. The cover may be bolted lirn'ily to the tank by bolts engaging ears on the tank and cover, respectively, as seen in Figs. 1 and 2, and the tank ma-y be provided with handles 22:3 23 to l'acilitate its removal from the attached parts `for change of oil or other attention.

A switch as thus constructed does not loul at the contacts with deposits oiz carbon, since the closing-and-opening action scrapes ell' l'rom the lower sides ot the fixed contact the deposits of carbon, which drop to the bottom of the vessel, and the smooth laces olE the terminal supports permit easy cleansing in case olt small deposits. Such a switch has proven el'lectivc for extremely high voltages over a long period ol! service.

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What we claim as new, and desire to sc- .cure by Letters Patent of the United States, is

lmovable contacts in the oil downwardly Vfrom the 'fixed contacts when opening the circuit, and upwardly into engagement with said Vfixed contacts when closing the circuit.

2. A high-potential switch for electric currents, comprising an oil-chamber, and circuit making and breaking contacts beneath the surface of the oil in said chamber, the movablecontacts being shaped to symmetrically displace the oil with relation to the arc formed at the point of rupture.

3. A high-potential switch, comprising an oil-chamber containing the circuit making and breaking contacts beneath the surface of the oil, means for separating the contacts, an d means for preventing irregular oil-cddies at the point of rupture.

4. A high-potential switch comprising an oil-chamber, contacts Vfor making and breaking the circuit beneath the oil in the chamber, the movable contact being provided with a cutting edge to cleave the oil in the direction of opening the circuit.

5. A high-potential switch having Yfixed contacts, an oil-bath. submerging the same, a cover Vfor the vessel containing the oil, hollow insulators supported thereby for the ilixed contacts, and movable contacts Vfor making and breaking the circuit guided by said cover.

6. A high-potential switch for electric currents, comprising an oil-chamber, fixed contacts supported therein beneath the oil-level and insulated therefrom, a metallic bridge for coupling the contacts, an insulating-rod extending outside the oil-chamber and connected to the bridge, an operating-handle Yfor raising and lowering the rod, and a toggle 'for cramping the switch in its closed position.

7 A high-potential switch for electric currents, comprising a chamber containing an insulating liquid, circuit making and breaking contacts beneath the liquid surface, a reciprocatory movable contact, and means for drawing the are, in rupturing the circuit, downwardly in the liquid.

8. A high-potential switch for electric currents, comprising a chamber containing an insulating liquid, iixed terminals beneath the surface of the liquid having the contact-surface toward the bottom, a movable contact device, and means for shifting it downwardly 'from the 'fixed contacts in opening the circuit and upwardly over the same path in closing the circuit.

9. A high-potential switch for electric currents, comprising a chamber containing an insulating liquid, a plurality of fixed contacts beneath the liquid-level 'facing the bottom, a bridging-contact, an insulating-rod carrying the same extending outside of the liquid, and an operating device 'for raising and lowering the rod.

10. A high-potential switch for electric currents, comprising an oil-chamber, fixed contacts beneath the oil, movable contacts, guides 'for the same, levers 'for raising and lowering said contacts, a toggle to lock the switch closed, and means Afor cramping and collapsing the toggle.

11. A high-potential switch -for electric currents, comprising an oil-chamber, Vfixed contacts beneath the oil-level, composed of a plurality of yielding metal fingers projecting downwardly, and a vertically-movable contact adapted to wedge apart said Vlingers by an upward movement.

1.2. A high-potential switch for electric currents, comprising an oil-chamber, Afixed contacts beneath the oil-level each composed of a plurality of yielding metal lingers, and a movable contact to engage the lingers shifting downwardly to break the circuit.

13. A high-potential switch for electric currents, comprising an oil-chamber, separable contacts beneath the oil-level composed of a plurality of spring-fingers, arcing-tips on said lingers, and a downwardly-moving contact cooperating therewith.

14. A high-potential switch for polyphase currents, comprising an oil-chamber, a plurality of Yfixed terminals for each phase, in ovable bridging-contacts, in sulating-rods carrying the same, and means for lowering said rods to open all phases simultaneously by a downwardbreak.

In witness whereof we have hereunto set our hands this 12th day of February, 1901.

WILLIAM L. R. EMMET. EDVARD M. HEVLETT.

Vitnesses:

BENJAMIN B. HULL, EDWARD WILLIAMS, Jr.

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